Sickle Cell Trait: What is Sickle Cell Anemia

What is Sickle Cell Trait?

Sickle cell trait is not actually a disease, rather it is a health condition in which one of the two hemoglobin genes are defective. Hemoglobin is an essential oxygen transporting substance present in the red blood cells (RBCs). Sickle cell trait is also referred to as sicklemia. In sickle cell trait, one of the gene is responsible for forming normal hemoglobin (A) and the other for sickle hemoglobin (S). Normal hemoglobin is represented by AA, whereas sickle cell trait is symbolized by AS.

Persons with sickle cell trait do not develop recurrent symptoms, since there is presence of a normal hemoglobin gene. Some of the symptoms are prolonged headache, acidosis, heat stroke, liver disease, increased incidence of urinary track infections and renal carcinoma. During rigorous exercise or sport activities, a patient of sickle cell trait may suffer from increased exhaustion or dehydration, which at times can be fatal. Sickle cell trait may cause mild to severe complications, especially observed due to polymerization of hemoglobin S and gene mutation.

It is obvious that a person inherits one hemoglobin gene from each of the parents. Hence, the defective gene, hemoglobin S, can be either from the mother or the father. As the name suggests, the shape of RBCs with hemoglobin S are abnormally curved, thus resembling sickles (instead of the normal round shapes). The occurrence of sickle cell trait is highest in West Africa, where about 25 percent of the population inherits this condition.

What is Sickle Cell Anemia?

Sickle cell anemia, on the other hand, is a severe blood disease, which occurs when both the hemoglobin genes are defective. A person suffering from sickle cell anemia inherits one sickle cell gene from each of the parents, thus resulting in SS. There are many severe complications of sickle cell anemia. In comparison to the normal RBCs, sickle-shaped RBCs do not move freely in the bloodstream, rather they tend to stick together, form clumps and clog the blood vessels. Usually, they are more stiff and fragile than the normal RBCs. Overall, this affects the normal functioning of the body parts by hampering the oxygen distribution.

The sickle-shaped RBCs last for only 10 - 20 days, which is comparatively less than normal RBCs that last for as long as 40 days. Consequently, the RBC count of a patient suffering from sickle cell anemia is lower than the normal recommended level, which is a condition referred to as anemia. Hence, the term sickle cell anemia is given for this health condition. Notable symptoms of sickle cell anemia are increased fatigue, weakness, jaundice, blood circulation problems, infections, weakened immune system and body aches. At times, the abnormal RBCs may be trapped in the lungs, leading to a condition called acute chest syndrome.

Diagnosis of sickle cell trait and sickle cell anemia is done by conducting hemoglobin electrophoresis, which is a technique to check the presence of sickle-shaped RBCs. There is no cure for these health conditions; treatment is usually done to alleviate the complications. Intravenous injections are given for controlling intense pain. In severe cases, blood transfusion is prescribed for incorporating healthy RBCs. Finding a cure for sickle cell trait and sickle cell anemia is a major challenge for scientists and researchers. Studies on gene therapy techniques are ongoing, so as to apply these techniques as an effective treatment for these blood disorders.